This invention relates to aircraft lightning protection and more particularly to an improved lightning diverter strip for aircraft.
It is well known that aircraft, when flying in the vicinity of thunderstorms, are subject to lightning strikes. Various points and regions of the aircraft extremities are subject to the formation of streamers prior to the actual lightning strike. It is also known that the lightning strike will occur when a leader connects up with one of the streamers, and the resulting current can reach as high as 200,000 amperes. While the aluminum aircraft skin is seldom subject to severe lightning damage by reason of its electrical conductivity, lightning attachments at certain critical points, for example, the radome section, are to be avoided due to the likelihood of damage to the electrical equipment.
Lightning diverter strips have been devised in the past for application to aircraft structural surfaces for the purpose of providing a non-destructive, electrically-conducted path to protect the underlying structure from direct lightning attachments. For example, thin metal foil strips and solid metal bars have been used to divert the charge. In addition, a series of closely spaced metal disks or dots have been applied to flexible strip material. In such instances, metal disks of 1/10 inch diameter have been bonded to a substrate, and the latter has been fixed by an epoxy adhesive to the outer surface of the radome to provide an ionized conductive path. While such an arrangement has been successful, it is of relatively high cost, and the relatively large disks absorb a great deal of heat and occasionally these disks have been known to explode and shoot out like pellets, especially if they are spaced too far apart. Also, the size of the disks adversely affect the radio frequency absorption of the strip.